Until relative humidity hits 100% at 80F and you hate your life (and your house due to the condensing moisture). Air conditioning is in large part about humidity control which using the ground will actually increase as best I can tell.

Not sure how far down you can go in Houston before you're under water. Downtown is only 15m above sea level apparently.

https://en.wikipedia.org/wiki/Geography_of_Houston

You know nothing about Houston if you think we can go "down" at all without digging a swimming pool.

Humidity is as much the enemy here as heat. AC is how we mitigate that.

Well, sure. There are lots of places in the US (and elsewhere) where you don't really need AC. It helps to have good ventilation, maybe some fans, and possibly other passive cooling. Maybe just deal with a week or two of uncomfortably hot weather during the summer.

Of course, it also helps to live in a house that is out in the country or at least suburbs rather than a city apartment. A window AC unit or two also can help for things like cooling a bedroom for the hottest nights.

Houston is beside the ocean and in generally swampy areas. Its average humidity range is between 60 and 90 percent depending on time of day. Hard to evaporate in those conditions.

No even close. It's basically on the gulf coast and for the hot half of the year at least very humid.

Also, barely above sealevel, so lots of techniques don't work.

Climate wise, it's a pretty uncomfortable place to live.

This article ranked 50 US cities by humidity:

https://www.gobankingrates.com/making-money/economy/most-hum...

Houston got the #3 spot. Only New Orleans and San Francisco are more humid.

(Another city on the list: El Paso, TX at #47.)

Houston (https://en.wikipedia.org/wiki/Houston) is absolutely not dry in the least. I'm guessing here, but I'd be hard pressed to name a more consistently humid US city.

Obviously, Texas is a single place to people who don't live here, but be aware that at 269K square miles (686K sq km), it's fucking huge. It's almost 800 miles across (ie, the distance between Louisiana and New Mexico).

So there's LOTS of variety in climate. The dry climate you associate with movie-Texas does definitely exist, but mostly in the western half of the state, & especially as you move down towards the Mexican border.

Houston, however, sits on the Gulf Coast. (Houston proper isn't on the water, but the overall metro area includes Galveston, which is an island in the Gulf.) The Gulf Stream curves over us and keeps us warm and wet.

Not for nothing, but our annual rainfall is pretty insanely high (~49 inches).

See more:

https://en.wikipedia.org/wiki/Climate_of_Houston

Anyway, in a very humid place like this, swamp coolers that depend on evaporation are of limited utility.